source: imaps-frontend/node_modules/webpack/hot/dev-server.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Tobias Koppers @sokra
*/
/* globals __webpack_hash__ */
if (module.hot) {
        /** @type {undefined|string} */
        var lastHash;
        var upToDate = function upToDate() {
                return /** @type {string} */ (lastHash).indexOf(__webpack_hash__) >= 0;
        };
        var log = require("./log");
        var check = function check() {
                module.hot
                        .check(true)
                        .then(function (updatedModules) {
                                if (!updatedModules) {
                                        log(
                                                "warning",
                                                "[HMR] Cannot find update. " +
                                                        (typeof window !== "undefined"
                                                                ? "Need to do a full reload!"
                                                                : "Please reload manually!")
                                        );
                                        log(
                                                "warning",
                                                "[HMR] (Probably because of restarting the webpack-dev-server)"
                                        );
                                        if (typeof window !== "undefined") {
                                                window.location.reload();
                                        }
                                        return;
                                }

                                if (!upToDate()) {
                                        check();
                                }

                                require("./log-apply-result")(updatedModules, updatedModules);

                                if (upToDate()) {
                                        log("info", "[HMR] App is up to date.");
                                }
                        })
                        .catch(function (err) {
                                var status = module.hot.status();
                                if (["abort", "fail"].indexOf(status) >= 0) {
                                        log(
                                                "warning",
                                                "[HMR] Cannot apply update. " +
                                                        (typeof window !== "undefined"
                                                                ? "Need to do a full reload!"
                                                                : "Please reload manually!")
                                        );
                                        log("warning", "[HMR] " + log.formatError(err));
                                        if (typeof window !== "undefined") {
                                                window.location.reload();
                                        }
                                } else {
                                        log("warning", "[HMR] Update failed: " + log.formatError(err));
                                }
                        });
        };
        var hotEmitter = require("./emitter");
        hotEmitter.on("webpackHotUpdate", function (currentHash) {
                lastHash = currentHash;
                if (!upToDate() && module.hot.status() === "idle") {
                        log("info", "[HMR] Checking for updates on the server...");
                        check();
                }
        });
        log("info", "[HMR] Waiting for update signal from WDS...");
} else {
        throw new Error("[HMR] Hot Module Replacement is disabled.");
}